String.GetEnumerator 方法
定義
擷取可以逐一查看這個字串中個別字元的物件。Retrieves an object that can iterate through the individual characters in this string.
public:
CharEnumerator ^ GetEnumerator();public CharEnumerator GetEnumerator ();member this.GetEnumerator : unit -> CharEnumeratorPublic Function GetEnumerator () As CharEnumerator傳回
列舉程式物件。An enumerator object.
範例
下列範例會將數個字串中的字元逐一查看，並顯示其個別字元的相關資訊。The following example iterates the characters in several strings and displays information about their individual characters. 它會使用語言反復專案結構，而不是呼叫 GetEnumerator 方法。It uses the language iteration construct rather than a call to the GetEnumerator method.
using namespace System;
void EnumerateAndDisplay(String^ phrase)
{
Console::WriteLine("The characters in the string \"{0}\" are:",
phrase);
int CharCount = 0;
int controlChars = 0;
int alphanumeric = 0;
int punctuation = 0;
for each (Char ch in phrase) {
Console::Write("'{0}' ", (! Char::IsControl(ch)) ? ch.ToString() :
"0x" + Convert::ToUInt16(ch).ToString("X4"));
if (Char::IsLetterOrDigit(ch))
alphanumeric++;
else if (Char::IsControl(ch))
controlChars++;
else if (Char::IsPunctuation(ch))
punctuation++;
CharCount++;
}
Console::WriteLine("\n Total characters: {0,3}", CharCount);
Console::WriteLine(" Alphanumeric characters: {0,3}", alphanumeric);
Console::WriteLine(" Punctuation characters: {0,3}", punctuation);
Console::WriteLine(" Control Characters: {0,3}\n", controlChars);
}
int main()
{
EnumerateAndDisplay("Test Case");
EnumerateAndDisplay("This is a sentence.");
EnumerateAndDisplay("Has\ttwo\ttabs");
EnumerateAndDisplay("Two\nnew\nlines");
}
// The example displays the following output:
// The characters in the string "Test Case" are:
// 'T' 'e' 's' 't' ' ' 'C' 'a' 's' 'e'
// Total characters: 9
// Alphanumeric characters: 8
// Punctuation characters: 0
// Control Characters: 0
//
// The characters in the string "This is a sentence." are:
// 'T' 'h' 'i' 's' ' ' 'i' 's' ' ' 'a' ' ' 's' 'e' 'n' 't' 'e' 'n' 'c' 'e' '.'
// Total characters: 19
// Alphanumeric characters: 15
// Punctuation characters: 1
// Control Characters: 0
//
// The characters in the string "Has two tabs" are:
// 'H' 'a' 's' '0x0009' 't' 'w' 'o' '0x0009' 't' 'a' 'b' 's'
// Total characters: 12
// Alphanumeric characters: 10
// Punctuation characters: 0
// Control Characters: 2
//
// The characters in the string "Two
// new
// lines" are:
// 'T' 'w' 'o' '0x000A' 'n' 'e' 'w' '0x000A' 'l' 'i' 'n' 'e' 's'
// Total characters: 13
// Alphanumeric characters: 11
// Punctuation characters: 0
// Control Characters: 2
using System;
class Example
{
public static void Main()
{
EnumerateAndDisplay("Test Case");
EnumerateAndDisplay("This is a sentence.");
EnumerateAndDisplay("Has\ttwo\ttabs" );
EnumerateAndDisplay("Two\nnew\nlines");
}
static void EnumerateAndDisplay(String phrase)
{
Console.WriteLine("The characters in the string \"{0}\" are:",
phrase);
int CharCount = 0;
int controlChars = 0;
int alphanumeric = 0;
int punctuation = 0;
foreach (var ch in phrase) {
Console.Write("'{0}' ", ! Char.IsControl(ch) ? ch.ToString() :
"0x" + Convert.ToUInt16(ch).ToString("X4"));
if (Char.IsLetterOrDigit(ch))
alphanumeric++;
else if (Char.IsControl(ch))
controlChars++;
else if (Char.IsPunctuation(ch))
punctuation++;
CharCount++;
}
Console.WriteLine("\n Total characters: {0,3}", CharCount);
Console.WriteLine(" Alphanumeric characters: {0,3}", alphanumeric);
Console.WriteLine(" Punctuation characters: {0,3}", punctuation);
Console.WriteLine(" Control Characters: {0,3}\n", controlChars);
}
}
// The example displays the following output:
// The characters in the string "Test Case" are:
// 'T' 'e' 's' 't' ' ' 'C' 'a' 's' 'e'
// Total characters: 9
// Alphanumeric characters: 8
// Punctuation characters: 0
// Control Characters: 0
//
// The characters in the string "This is a sentence." are:
// 'T' 'h' 'i' 's' ' ' 'i' 's' ' ' 'a' ' ' 's' 'e' 'n' 't' 'e' 'n' 'c' 'e' '.'
// Total characters: 19
// Alphanumeric characters: 15
// Punctuation characters: 1
// Control Characters: 0
//
// The characters in the string "Has two tabs" are:
// 'H' 'a' 's' '0x0009' 't' 'w' 'o' '0x0009' 't' 'a' 'b' 's'
// Total characters: 12
// Alphanumeric characters: 10
// Punctuation characters: 0
// Control Characters: 2
//
// The characters in the string "Two
// new
// lines" are:
// 'T' 'w' 'o' '0x000A' 'n' 'e' 'w' '0x000A' 'l' 'i' 'n' 'e' 's'
// Total characters: 13
// Alphanumeric characters: 11
// Punctuation characters: 0
// Control Characters: 2
Module Example
Sub Main()
EnumerateAndDisplay("Test Case")
EnumerateAndDisplay("This is a sentence.")
EnumerateAndDisplay("Has" & vbTab & "two" & vbTab & "tabs")
EnumerateAndDisplay("Two" & vbLf & "new" & vbLf & "lines")
End Sub
Sub EnumerateAndDisplay(phrase As String)
Console.WriteLine("The characters in the string ""{0}"" are:", phrase)
Dim charCount As Integer = 0
Dim controlChars As Integer = 0
Dim alphanumeric As Integer = 0
Dim punctuation As Integer = 0
For Each ch In phrase
Console.Write("'{0}' ", If(Not Char.IsControl(ch), ch,
"0x" + Convert.ToUInt16(ch).ToString("X4")))
If Char.IsLetterOrDigit(ch) Then
alphanumeric += 1
Else If Char.IsControl(ch) Then
controlChars += 1
Else If Char.IsPunctuation(ch) Then
punctuation += 1
End If
CharCount += 1
Next
Console.WriteLine()
Console.WriteLine(" Total characters: {0,3}", CharCount)
Console.WriteLine(" Alphanumeric characters: {0,3}", alphanumeric)
Console.WriteLine(" Punctuation characters: {0,3}", punctuation)
Console.WriteLine(" Control Characters: {0,3}", controlChars)
Console.WriteLine()
End Sub
End Module
' This example displays the following output:
' The characters in the string "Test Case" are:
' 'T' 'e' 's' 't' ' ' 'C' 'a' 's' 'e'
' Total characters: 9
' Alphanumeric characters: 8
' Punctuation characters: 0
' Control Characters: 0
'
' The characters in the string "This is a sentence." are:
' 'T' 'h' 'i' 's' ' ' 'i' 's' ' ' 'a' ' ' 's' 'e' 'n' 't' 'e' 'n' 'c' 'e' '.'
' Total characters: 19
' Alphanumeric characters: 15
' Punctuation characters: 1
' Control Characters: 0
'
' The characters in the string "Has two tabs" are:
' 'H' 'a' 's' '0x0009' 't' 'w' 'o' '0x0009' 't' 'a' 'b' 's'
' Total characters: 12
' Alphanumeric characters: 10
' Punctuation characters: 0
' Control Characters: 2
'
' The characters in the string "Two
' new
' lines" are:
' 'T' 'w' 'o' '0x000A' 'n' 'e' 'w' '0x000A' 'l' 'i' 'n' 'e' 's'
' Total characters: 13
' Alphanumeric characters: 11
' Punctuation characters: 0
' Control Characters: 2
備註
提示
您應該改用語言的反復專案結構（在C#中為，在C++/clr 中，在 Visual Basic 中），而不是呼叫 GetEnumerator 方法來取出用來列舉字串的 CharEnumerator 物件。Rather than calling the GetEnumerator method to retrieve a CharEnumerator object that you then use to enumerate a string, you should instead use your language's iteration construct (in C#, in C++/CLR, and in Visual Basic). C#中的foreach ，針對 C++/clr 中的每個，和 Visual Basic 中的每個）。foreach in C#, for each in C++/CLR, and For Each in Visual Basic).
這個方法可讓您逐一查看字串中的個別字元。This method enables you to iterate the individual characters in a string. 例如，Visual Basic For Each 和C#foreach語句會叫用這個方法，以傳回可提供此字串實例中字元之唯讀存取權的CharEnumerator物件。For example, the Visual Basic For Each and C# foreach statements invoke this method to return a CharEnumerator object that can provide read-only access to the characters in this string instance.